Influence of Processing on Mechanical Properties of Hydroxyapatite

2008 ◽  
Vol 396-398 ◽  
pp. 587-590
Author(s):  
Marize Varella de Oliveira ◽  
Magna Monteiro Schaerer ◽  
Robson Pacheco Pereira ◽  
Ieda Maria V. Caminha ◽  
Silvia R. A. Santos ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Processing Parameters ◽  
Molar Ratio ◽  
Micro Hardness ◽  
Sem Images ◽  
Cross Sectional ◽  
Load To Failure ◽  
Cylindrical Samples ◽  
Vickers Micro Hardness

In the present work, mechanical properties of a stoichiometric hydroxyapatite (HA), synthesized by hydrothermal method, with 1.66 Ca/P molar ratio are investigated as a function of the processing parameters. Cylindrical samples were processed by uniaxial compacting, followed by sintering, aiming to obtain high density HA samples. Density values were obtained by the geometric method and SEM images were taken from HA samples in order to characterize their topography and to determine the grain size for each set of samples. Vickers micro-hardness was measured for each set of samples. Compressive strength of cylindrical samples with 2.0 mean diameter/height ratio was measured reporting load to failure divided by the cross-sectional area of the samples. Vickers micro-hardness and compaction strength values of the samples were found to be in agreement with the relative density and grain size values.

Microstructural and Mechanical Characterization of Sintered Hydroxyapatite Samples

2008 ◽  
Vol 591-593 ◽  
pp. 717-721 ◽  
Author(s):  
Marize Varella de Oliveira ◽  
Magna Monteiro Schaerer ◽  
Silvia R. A. Santos ◽  
Ieda Maria V. Caminha ◽  
Antonella M. Rossi
Keyword(s):  
Compressive Strength ◽  
Bone Repair ◽  
Microstructural Characterization ◽  
Molar Ratio ◽  
Body Parts ◽  
Cross Sectional ◽  
Load To Failure ◽  
Cylindrical Samples ◽  
Medium Diameter

Despite of the wide use of hydroxyapatite (HA) for bone repair and regeneration, its brittleness has limited clinical application to less stressed body parts. Thus, evaluation of HA mechanical properties has been an important research matter. The aim of this study is to assess the compressive strength of a stoichiometric HA with 1.66 Ca/P molar ratio, synthesized by hydrothermal method. Cylindrical samples were processed by uniaxial compacting, followed by sintering. Compressive strength of cylindrical samples with 2.0 medium diameter/height ratio was measured according to ASTM C 1424. Load to failure divided by the cross-sectional area of the samples were reported and microstructural characterization was made by MEV-EDS. The compression strength results were compared to values reported in the literature.

Surface Modification and its Influence on the Microstructure and Creep Resistance of Nickel Based Superalloy René 77 / Modyfikacja Powierzchniowa Oraz Jej Wpływ Na Mikrostrukture I Wytrzymałosc Na Pełzanie Odlewów Z Nadstopu Niklu Ren´E 77

2013 ◽  
Vol 58 (1) ◽  
pp. 95-98 ◽  
Author(s):  
M. Zielinska ◽  
J. Sieniawski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Surface Modification ◽  
Turbine Blades ◽  
Processing Parameters ◽  
Grain Structure ◽  
Creep Tests ◽  
Cobalt Aluminate ◽  
Nickel Based Superalloy ◽  
Average Grain Size

Superalloy René 77 is very wide used for turbine blades, turbine disks of aircraft engines which work up to 1050°C. These elements are generally produced by the investment casting method. Turbine blades produced by conventional precision casting methods have coarse and inhomogeneous grain structure. Such a material often does not fulfil basic requirements, which concern mechanical properties for the stuff used in aeronautical engineering. The incorporation of controlled grain size improved mechanical properties. This control of grain size in the casting operation was accomplished by the control of processing parameters such as casting temperature, mould preheating temperature, and the use of grain nucleates in the face of the mould. For nickel and cobalt based superalloys, it was found that cobalt aluminate (CoAl2O4) has the best nucleating effect. The objective of this work was to determine the influence of the inoculant’s content (cobalt aluminate) in the surface layer of the ceramic mould on the microstructure and mechanical properties at high temperature of nickel based superalloy René 77. For this purpose, the ceramic moulds were made with different concentration of cobalt aluminate in the primary slurry was from 0 to 10% mass. in zirconium flour. Stepped and cylindrical samples were casted for microstructure and mechanical examinations. The average grain size of the matrix ( phase), was determined on the stepped samples. The influence of surface modification on the grain size of up to section thickness was considered. The microstructure investigations with the use of light microscopy and scanning electron microscopy (SEM) enable to examine the influence of the surface modification on the morphology of ’ phase and carbides precipitations. Verification of the influence of CoAl2O4 on the mechanical properties of castings were investigated on the basis of results obtained form creep tests.

scholarly journals Mechanical and structural properties of composites made from recycled and virgin polyethylene terephthalate (PET) and metal chip or mesh wire

2019 ◽  
Vol 299 ◽  
pp. 06007
Author(s):  
Mircea Aurelian Antoniu Rusu ◽  
Sever-Adrian Radu ◽  
Catalin Moldovan ◽  
Codruta Sarosi ◽  
Ionela Amalia Mazilu (Moldovan) ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyethylene Terephthalate ◽  
Processing Parameters ◽  
Sem Images ◽  
Major Drawback ◽  
Recycled Pet ◽  
Plastic Processing ◽  
Metal Chip ◽  
Intense Research ◽  
Properties Of Composites

Although polyethylene terephthalate (PET) is a champion of recycling, intense research is being done to find new solutions for using recycled plastic. This study aims to characterize the mechanical andstructural properties (SEM- scanning electron microscopy) of products made from recycled metal swarf or mesh wire with recycled plastic (PET) in comparison with virgin plastic. Samples manufactured from virgin and recycled PET are made by pressing and high temperature. The loss of mechanical properties ofproducts made from recycled plastic is a major drawback that influences their use. SEM images confirm that the dispersion and distribution of the PET phase is not very uniform. By addition of virgin plastic in various compositions with recycled plastic, processing parameters and mechanical properties can be optimized.

The Use of Bobbin Tools for Friction Stir Welding of Aluminium Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 1179-1184 ◽  
Author(s):  
Philip L. Threadgill ◽  
M.M.Z. Ahmed ◽  
Jonathan P. Martin ◽  
Jonathan G. Perrett ◽  
Bradley P. Wynne
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Friction Stir Welding ◽  
Cross Section ◽  
Axial Force ◽  
Aluminium Alloys ◽  
Processing Parameters ◽  
Machine Design ◽  
Friction Stir ◽  
Triangular Zone

The use of a double sided friction stir welding tool (known as a bobbin tool) has the advantage of giving a processed zone in the workpiece which is more or less rectangular in cross section, as opposed the triangular zone which is more typically found when conventional friction stir welding tool designs are used. In addition, the net axial force on the workpiece is almost zero, which has significant beneficial implications in machine design and cost. However, the response of these tools in generating fine microstructures in the nugget area has not been established. The paper presents detailed metallographic analyses of microstructures produced in 25mm AA6082-T6 aluminium wrought alloy, and examines grain size, texture and mechanical properties as a function of processing parameters and tool design, and offers comparison with data from welds made with conventional tools.

Tem Investigation and Hardness Improvement of A N+ Implanted Al-Alloy

1995 ◽  
Vol 400 ◽  
Author(s):  
A.M. Serventi ◽  
M. Vittori Antisari ◽  
L. Guzman ◽  
A. Miotello
Keyword(s):  
Ion Beam ◽  
Al Alloy ◽  
Micro Hardness ◽  
Cross Sectional ◽  
Hardness Tests ◽  
First Results ◽  
Different Temperatures ◽  
Nitrogen Ion ◽  
A Current ◽  
Vickers Micro Hardness

AbstractThe surface modification induced by nitrogen ion implantation on the Al-alloy 7075 has been studied with the aim of understanding the microstructural evolution and the phase separation during the implantation process. 150 keV N2+ ions have been implanted at different temperatures from 373 K to 473 K, with a current density of 5–15 µA/cm2 on previously polished samples. The implanted dose was in the range 1 × 1017 N/cm2 - 5 × 1017 N/cm2. Vickers micro-hardness tests and friction coefficient measurements show a real improvement in the mechanical behaviour of the alloy after the treatment.TEM observations of specimens treated at low temperature with different ion dose have been carried out at 200 kV on cross-sectional samples, prepared by ion beam milling. First results show the presence of small AlN hexagonal precipitates whose evolution is followed as a function of the implanted dose.

Finite Element Modeling of Grain Size Effect on the Mechanical Properties and Deformability of Titanium Alloy in Equal Channel Angular Pressure

2015 ◽  
Vol 661 ◽  
pp. 91-97
Author(s):  
Cho-Pei Jiang ◽  
Zong Han Huang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Finite Element ◽  
Titanium Alloy ◽  
Tensile Test ◽  
Annealing Treatment ◽  
Cross Sectional ◽  
Squeeze Pressure ◽  
Brittle Behavior ◽  
Β Phase

The aim of this research is to investigate the effect of grain size on the mechanical properties and deformability of titanium alloy in equal channel and cross-sectional reduction channel angular pressing process. Specimens made of grade 2 titanium alloy with diameter 5 mm are annealed to temperature of 500 °C to 1000 °C resulting in different initial grain sizes, thus underwent tensile test for obtaining mechanical properties. Molds for both processes are designed to carry out serve plastic deformation. Finite element models are created and simulated the deformation behavior according to the mechanical properties of tensile test. Experimental results show that small α-phase grain starts to form in 700 °C homogenization treatment and its grain size increases as an increasing of annealing temperature. The β-phase microstructure precipitates resulting in brittle behavior in 850 °C annealing treatment. Simulation result show that squeeze load of ECAP is larger than 100 ton but it can be reduced when exit angle of channel is larger than entrance. Outer corner of ECAP with 90 ̊ generate lower squeeze pressure than that of 40 ̊.

Strain Hardening in Polycrystalline and Nanocrystalline Nickel

2011 ◽  
Vol 409 ◽  
pp. 550-554 ◽  
Author(s):  
B.T.F. Tang ◽  
Uwe Erb ◽  
I. Brooks
Keyword(s):  
Grain Size ◽  
Strain Hardening ◽  
Bulk Material ◽  
Micro Hardness ◽  
Polycrystalline Nickel ◽  
Nanocrystalline Nickel ◽  
Indentation Analysis ◽  
Hardness Values ◽  
Vickers Micro Hardness ◽  
Considerable Strain

The work hardening behavior of electrodeposited nanocrystalline (grain size: 100 nm) and fully annealed polycrystalline nickel (grain size: 160 µm) was examined by hardness indentation analysis. First, plastic strain was introduced into the materials through large Rockwell hardness indentations. A series of Vickers micro-hardness traces below and away from the Rockwell indentation then measured the change in hardness as a function of distance from the plastic zone. The results showed that polycrystalline nickel exhibited considerable strain hardening, with micro-hardness values closest to the Rockwell indentation averaging twice the hardness value of the bulk material. On the other hand, for the nanocrystalline nickel the Vickers micro-hardness values changed only by a few percent indicating a limited strain hardening capacity.

Effect of Equal Channel Angular Extrusion on the Microstructure and Mechanical Properties of Magnesium Alloy Containing Quasicrystallines

2005 ◽  
Vol 488-489 ◽  
pp. 589-592 ◽  
Author(s):  
Ming Yi Zheng ◽  
Xiao Guang Qiao ◽  
Shi Wei Xu ◽  
Kun Wu ◽  
Shigeharu Kamado ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Ultimate Tensile Strength ◽  
Equal Channel Angular Extrusion ◽  
Extrusion Direction ◽  
Micro Hardness ◽  
Angular Extrusion ◽  
The Matrix

Equal channel angular extrusion (ECAE) was applied to an extruded ZW1101 (Mg - 11wt%Zn - 0.9wt%Y) Mg alloy containing quasicrystallines. The as-extruded ZW1101 alloy had an initial grain size of about 12 µm and bands of quasicrystalline phases parallel to the extrusion direction. After the extruded alloy was subjected to ECAE processing, the grain size was refined to about 0.5 µm, and the quasicrystalline phases were further broken and dispersed in the matrix. After the ECAE processing, the micro-hardness and yield strength of the alloy were increased, however, the ultimate tensile strength and the ductility of the alloy were slightly decreased.

Effect of As-Processed and Annealed Microstructures on the Mechanical Properties of Liga Ni MEMS

1999 ◽  
Vol 605 ◽  
Author(s):  
Z. L. Xie ◽  
D. Pan ◽  
H. Last ◽  
K. J. Hemker
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Tensile Testing ◽  
Grain Morphology ◽  
Columnar Microstructure ◽  
Dramatic Decrease ◽  
Cross Sectional ◽  
Property Relations ◽  
Size And Morphology

AbstractMicrostructure – mechanical property relations of 200 μm thick LIGA deposited Ni films have been investigated with a combination of optical cross-sectional microscopy and microsample tensile testing. Measurements of the grain size and morphology of nine different asdeposited films evidenced a predominantly columnar microstructure with significant variations in grain size. These as-deposited microstructural variations resulted in a range of Young's modulus, yield strength, and ultimate tensile strength values that are consistent with previously reported measurements, but these values did not appear to scale with the as-deposited microstructures. By contrast, significant changes in both the microstructure and mechanical properties were observed when these films were annealed at 800'C for 1 hour. Recrystallization and grain growth transformed the grain morphology from columnar to equiaxed, which resulted in a dramatic decrease in the tensile strength and corresponding increase in the ductility of the annealed films.

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